Had this experience more than once, but the one that comes to mind:
In high school chemistry, the teacher was reviewing what we should remember from lower school about atoms & molecules (single bonds, double bonds, slots available for single atoms of different elements). I asked something like "If the model we were using treats the bonding sites on every atom of every element as equal, but says that some molecules are either rarer than others or not known to occur in nature, doesn't that mean the model is incomplete or incorrect?". She instantly shook her head with annoyance and said sternly "No.".
From my limited experience (being a child and raising one child) I would say that the problem is more that we (as adults) pretend that the simplified thing is the whole picture.
Every time someone told me: "this is a simplified version to give you a basic understanding and later you will be able to learn more accurate versions" that was tremendously helpful and sometimes it sparked my curiosity and motivated me to look stuff up myself.
I mean we should get ahead of the realisation that it doesn't add up.
When I moved to the US in 3rd grade, I was marked wrong for putting negative numbers as answers on a math test. The correct answer was "You can't subtract a larger number from a smaller number".
I had a similar experience, but was fortunate that the teacher took me aside and explained that I was right but they were teaching a simplified version. In hindsight that was really a helpful approach.
I suspect that the best approach would be not to "get ahead", but rather see this realisation develop naturally and help it along the way. It's hard to get critical thinking if everything is already criticized before you even come.
This can work with your kids though but I don't know if it can be effectively scaled to a school class. Maybe on a few dedicated play/discovery sessions, not on a regular basis.
Doing this would create a nice opportunity to teach the right and wrong ways to move the needle in scientific discourse (e.g. don't start by holding a press conference about cold fusion).
Graduation could mean an overthrowing of the known-wrong models. Congratulations, here are the next known-wrong models. Now prove these wrong.
